JPH09261728A - Mobile communication area extension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend a radio zone by using optical fibers so as to connect a PHS base station to a radio base station equipment. SOLUTION: An antenna selector switch 42 of a PHS base station 41 is connected fixedly to a terminal (a) of a transmission reception changeover switch 43, an optical interface 51 connecting to antenna terminal equipments 41a, 41b of the base station 41 is connected to the distant radio base station equipment 52 with optical fibers 17, 31, and the equipment 52 employs antennas 45, 46, an antenna selector switch 57 and transmission reception changeover switches 58, 59 to be configured similarly to the case with the base station 41. Then the equipment 52 attain time division simultaneous transmission and reception (TDD) with a mobile terminal equipment 26, and an incoming signal from the antenna 46 is frequency-converted by a circuit 62, its output and a signal from the antenna 45 are synthesized, an electrooptic(E/O) converter 29 converts the synthesized signal into an optical signal, which is fed to the optical fiber 31. Its emitted light is converted into an electric signal by an optoelectric(O /E) converter 32, and given to a BPF 55, from which the signal from the antenna 45 is obtained and, also the output of the BPF 56 is given to a frequency conversion circuit 56, from which the signal from the antenna 46 is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a TDD (Time Division Duplexing) for a radio access system such as PHS and uses an electric / optical converter and an optical / electrical converter for a base station sharing an antenna for transmission and reception. By connecting an optical interface device composed of a converter and connecting this optical interface device with a wireless base station device that transmits and receives radio waves to and from a mobile terminal by an optical fiber, the wireless communication area is separated from the base station. The present invention relates to a wireless communication area expansion device in a mobile communication system in which a base station and a mobile terminal communicate with each other by expanding to a place where a wireless base station device is installed.

[0002]

2. Description of the Related Art In recent years, in a cellular system, development of a booster system using an optical fiber has been promoted with respect to a blind delay in an underground mall or the like. FIG. 5 shows a block diagram of an optical fiber booster system used in a cellular system. Although not shown in the figure via the interface 12, the cellular base station 11 is connected to a mobile communication exchange via a wired transmission path, for example, and a downlink signal from this mobile communication exchange is converted into a high frequency signal by a modulator 13, The signal is amplified by the amplifier 14 and converted into an optical signal by the electrical / optical converter 16 of the optical interface device 15, and the optical signal is incident on one end of the optical fiber 17. The optical fiber 17 is extended to, for example, a radio base station device 18 provided in an underground mall, an optical signal from the optical fiber 17 is converted into an electric signal by an optical / electrical converter 19 of the radio base station device 18, and the electric signal is converted into an electric signal. Transmission amplifier 2
1, is passed through the transmission bandpass filter 22, and is further transmitted from the antenna 24 through the transmission / reception separating circulator 23, for example, the wireless communication zone (cell) 25 in an underground mall.
Is emitted as a radio wave to.

A mobile terminal 26 moving in the radio communication zone 25 can transmit and receive radio waves to and from the radio base station device 18, and an up radio wave from the mobile terminal 26 is transmitted to the antenna 24.
Received by the circulator 23, further passes through the reception bandpass filter 27, is amplified by the reception amplifier 28, and is converted into an optical signal by the electric / optical converter 29. The optical signal is transmitted to the optical interface device 15 through the optical fiber 31.
The signal is transmitted to an electric converter 32, converted into an electric signal there, the electric signal is amplified by an amplifier 33 in the base station 11, demodulated by a demodulator 34, and the demodulated output is passed through the interface 12, for example, a mobile telecommunication switch. Transmitted to.

In the cellular system, as a radio access method, FDD (Frequenquen) which uses different frequencies for transmission and reception signals is used.
cy Division Duplexing: Frequency division simultaneous transmission / reception is used, and switching between transmission and reception is unnecessary. Therefore,
As shown in FIG. 5, the antenna terminal 11a of the base station 11
The optical fiber booster system can be easily realized by connecting the optical interface device 15 to 11b.

[0005]

On the other hand, in PHS, the TDD is adopted as the radio access method from the viewpoint of frequency utilization efficiency.
(Time Division Duplexing) is used. PH in Figure 6
In the block diagram of the base station 41 of S, the same reference numerals are given to the portions corresponding to those in FIG. The movable terminal of the antenna selection switch 42 is connected to the output side of the amplifier 14, and the fixed terminals 42a and 42b of the antenna selection switch 42 are connected to the fixed terminals 43a and 44a of the transmission / reception changeover switches 43 and 44, respectively. , 44 are connected to the antennas 45, 46 through the antenna terminals 41a, 41b. Fixed terminal 43 of transmission / reception changeover switches 43, 44
b and 44b are connected to the demodulators 34 and 48 through amplifiers 33 and 47, respectively, and the output side of the demodulator 48 is connected to the interface 12.

This apparatus has a transmission / reception diversity function, and the antenna selection switch 42 causes the antenna 45,
46 is switched to transmit. Further, in the TDD method, the antenna is shared for transmission and reception, so the transmission / reception changeover switch 43,
The transmission / reception is switched by 44. Therefore, when the optical fiber booster method is applied to the PHS base station, simply connecting the antenna terminal of the base station and the optical interface device as in the cellular system shown in FIG.
Since both 1a and 11b alternately switch between transmitting a transmission signal and receiving a reception signal, the transmission signal is transmitted to both the electric / optical converter 16 and the optical / electrical converter 32. Since it is necessary to perform transmission and reception of a reception signal, it is difficult to communicate normally.

An object of the present invention is to extend a mobile communication area by connecting a base station operating in the TDD system to a remote radio base station device via an optical fiber to extend the service area of the base station. To provide a device.

[0008]

According to the invention of claim 1, a radio base station apparatus is provided with an antenna selection switch similar to that of a base station, two transmission / reception changeover switches, and two antennas, and is similarly connected. Then, similarly, antenna selection control and transmission / reception switching control are performed, and one of the reception signals from the two antennas is converted into a frequency band by a frequency conversion circuit,
Combine with the other received signal and supply to the electro-optical converter,
The wireless base station device is required to have only one optical / electrical converter and one electric / optical converter. The optical interface device divides the converted output reception signal from the optical / electrical converter into two, and the wireless base station device from one side. The received signal that is not frequency-converted by is extracted by the band pass filter, the other is returned to the frequency before conversion by the frequency conversion circuit and is supplied to one antenna terminal of the base station, and is also sent to the other antenna terminal of the base station by the transmission / reception switch. The input side of the electric / optical converter and the output side of the band pass filter are switched and connected. The transmission / reception changeover switches of the base station, the optical interface device, and the wireless base station device are switched and controlled in synchronization with each other. However, it is a matter of course in the design to provide a time shift according to the transmission delay.

According to the second aspect of the present invention, n base stations are provided, and correspondingly, n transmission / reception changeover switches of the optical interface device are also provided, and each downlink signal has n frequencies at different frequencies. The converted output is converted by the conversion circuit, these converted outputs are combined and supplied to the optical / electrical converter, the output of the band-pass filter is distributed to the upstream reception signal by n, and the upstream reception signal is supplied to n transmission / reception changeover switches and frequency conversion is performed. The output of the circuit is divided into n and supplied to the second antenna terminals of the n base stations. In the wireless base station, the output of the optical / electrical converter is divided into n, and the n frequency conversion circuits restore the signal frequencies before the conversion of the n frequency conversion circuits in the optical interface device. To the movable terminal of the antenna selection switch, the output signals of one fixed terminal of these n antenna selection switches are combined and supplied to one of the transmission / reception changeover switches, and the output signals of the other fixed terminals are combined. Is supplied to the other transmission / reception changeover switch.

According to a fourth aspect of the present invention, the uplink received signal in the second aspect of the invention is such that, in the radio base station apparatus, n number of frequency conversions are performed by the respective antennas in different bands and different frequencies. Converted by the circuit, combined, transmitted as an optical signal to the base station, converted into an electrical signal by the optical interface device, distributed by 2n, returned to the original frequency by 2n frequency conversion circuits, and compatible with one antenna The n converted outputs are supplied to the n transmission / reception changeover switch, and the n converted outputs corresponding to the other antenna are supplied to the second antenna terminals of the n base stations.

According to the third aspect of the present invention, the diversity action is omitted, and the base station is fixed so that the antenna selection switch and the two transmission / reception changeover switches both constitute one transmission system and one reception system. In the wireless base station, the output side of the optical / electrical converter and the input side of the electric / optical converter are alternately connected to one antenna by the transmission / reception changeover switch.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the invention according to claim 1 with the same reference numerals being given to the parts corresponding to those in FIGS. The base station 41 uses a TDD scheme for wireless access, and has the same configuration as, for example, a normal PHS base station, that is, the same as that shown in FIG. An optical interface device 51 is connected to the antenna terminals 41a and 41b of the base station 41, and the optical interface device 51 uses the optical fiber 1
The wireless base station device 52 is connected to the wireless base station device 52 through 7 and 31, and the wireless base station device 52 transmits / receives wireless radio waves to / from the mobile terminal 26 moving in the mobile communication zone (cell) 25.

In the base station 41, the antenna selection switch 42
Is fixedly connected to the fixed terminal 43a of the transmission / reception changeover switch 43. The optical interface device 51 is provided with a transmission / reception changeover switch 53, the movable terminal of which is connected to the antenna terminal 41a of the base station 41, and the fixed terminal 53a is connected to an electric / optical converter (referred to as E / O) 16. The output signal of the optical / electrical converter (hereinafter referred to as O / E) 32 is distributed by the distributor 54.
And the upstream reception radio frequency of the radio base station device 52 is selected by the band pass filter 55 and supplied to the fixed terminal 53b of the transmission / reception changeover switch 53. The other distribution output signal of the distributor 54 is returned to the state before frequency conversion in the radio base station apparatus 52 by the frequency conversion circuit 56 and supplied to the antenna terminal 41b of the base station 41.

In the radio base station device 52, the antenna selection switch 42 and the transmission / reception changeover switches 43 and 44 of the base station 41 are included.
Similarly to the above, the antenna selection switch 57 and the transmission / reception changeover switches 58 and 59 are provided, and the connection is made in the same manner as the base station 41. The movable terminal of the antenna selection switch 57 is connected to the output side of the transmission amplifier 21, the movable terminals of the transmission / reception changeover switches 57 and 58 are connected to the antennas 45 and 46, respectively, and the fixed terminals 58b and 59b are the reception amplifiers 28 and 61, respectively. Connected to the input side of. Receiver amplifier 61
Is converted into a signal of a frequency other than the frequency band used in the mobile communication by the frequency conversion circuit 62, and the frequency conversion output is combined with the output signal of the reception amplifier 28 by the coupler 63 to be converted into the electric / optical converter. (Denoted as E / O) 29.

All transmission / reception changeover switches 43, 44, 5
3, 58 and 59 are synchronously switched, and the antenna selection switches 53 and 57 are synchronously switched. However, in actual operation, there is a time difference according to the transmission delay between these switches. In the downlink,
The output signal of the modulator 13 in the base station 41 is the transmission amplifier 1
After being amplified by 4, the signal is input from the switch 42 to the terminal 43a of the switch 43. The switch 43 is connected to the terminal 43a at the transmission timing, and the wireless electric signal is input from the switch 43 to the switch 53 in the optical interface device 51. The switch 53 is connected to the terminal 53a at the transmission timing, and the output signal of the terminal 53a is E /
Input to O16. As a result, the wireless electric signal is converted into an optical signal, and the wireless base station device 5 is transmitted via the optical fiber 17.
2 is input to O / E19. The optical signal is converted into a wireless electric signal by the O / E 19, amplified by the amplifier 21, and then input to the antenna selection switch 57. The antenna selection switch 57 is controlled by a control signal from a base station 41 (not shown) to be switch-connected to the transmission / reception changeover switches 58 and 59, and the wireless electric signal is input to the antenna 45 or 46 through the transmission / reception changeover switch 58 or 59. It is transmitted from the antenna 45 or 46 to the mobile terminal 26.
The transmission / reception changeover switches 58, 59 perform transmission / reception changeover control by a control signal from a base station (not shown).

On the uplink, the transmission signal from the mobile terminal 25 is transmitted to the antennas 45 and 46 of the radio base station apparatus 52.
And are input to the amplifiers 28 and 61 via the transmission / reception changeover switches 58 and 59, respectively. The output signal of the amplifier 61 is converted by the frequency conversion circuit 62 into a frequency band that does not overlap the entire signal frequency band assigned to the system used, and then combined with the output signal of the amplifier 28 by the combiner 63. The output signal of the coupler 63 is converted into an optical signal by the E / O 29 and then transmitted to the optical interface device 51 via the optical fiber 31. The optical signal from the wireless base station device 52 is transmitted to the optical interface device 5
It is converted into a wireless electric signal by the O / E 32 in 1 and the distributor 5
4 is input. The output signal of the distributor 54 is divided into two parts: a bandpass filter 55 and a frequency conversion circuit 56.
The band-pass filter 55 extracts the reception signal of the antenna 45 and inputs it to the terminal 53b of the switch 53. The switch 53 is connected to the terminal 53b at the reception timing, and is input to the switch 43 in the base station 41 from the terminal 53b. In the frequency conversion circuit 56, the reception signal of the antenna 46 is reconverted to the input frequency of the frequency conversion circuit 62 in the wireless base station device 52, extracted, and then input to the switch 44 in the base station 41. Switch 4 in base station 41
3 and 44 are terminals 43b and 44b at reception timing.
And wireless electric signals are connected to the switches 43 and 4 respectively.
4 to the amplifiers 33 and 47 respectively, and the amplifier 3
After being amplified by 3, 34, they are input to the demodulators 34, 48, respectively.

As described above, the TDD bidirectional communication is performed between the base station 41 and the mobile terminal 26, and the base station 41
Is a service for wireless zones 25 farther away,
It can be done via an optical fiber. Claim 3 in FIG.
1 shows the embodiment of the present invention, and parts corresponding to those in FIG. The difference from the embodiment of FIG. 1 is that transmission / reception diversity is not performed in this configuration, and no signal is input to the amplifier 33 and demodulator 34 in the base station 41. The transmission / reception changeover switches 43 and 44 are fixed terminals 43a and 44, respectively.
fixedly connected to b. The optical interface device 51 is provided with only E / O 16 and O / E 32, which are connected to the antenna terminals 41a and 41b, respectively.
The wireless base station device 52 is provided with only one antenna 45, and the antenna 45 is switchably connected to the amplifiers 21 and 28 by the transmission / reception changeover switch 57.

In the downlink, the output signal of the modulator 13 in the base station 41 is amplified by the transmission amplifier 14, and then E / O of the optical interface device 51 is passed through the switch 43.
16 is input. The wireless electric signal is converted into an optical signal by the E / O 16, and the wireless base station device 5 is transmitted through the optical fiber 17.
2 is input to O / E19. The optical signal is converted to a wireless electric signal in the O / E 19, amplified by the amplifier 21, input to the antenna 45 via the transmission / reception changeover switch 57, and transmitted from the antenna 45 to the mobile terminal 26.

In the uplink, the transmission signal from the mobile terminal 26 is received by the antenna 45 of the radio base station device 52 and input to the amplifier 28 via the transmission / reception changeover switch 57. The output signal of the amplifier 28 is converted into an optical signal by the E / O 29 and then transmitted to the optical interface device 51 via the optical fiber 31. The optical signal from the wireless base station device 52 is converted into a wireless electrical signal by the O / E 32 in the optical interface device 51 and transmitted to the switch 44 in the base station 41. The switch 44 is fixedly connected to the terminal 44b, and the wireless electric signal is input from the switch 44 to the amplifier 47, amplified by the amplifier 47, and then input to the demodulator 48.

For example, in PHS, the base station can process only three channels. That is, wireless zone 2
It is not possible to communicate with four or more mobile terminals 26 in 5 at the same time. When there is a lot of traffic in the wireless zone 25, it is necessary to install a plurality of base stations and synchronize them for operation. FIG. 3 shows an embodiment to which the present invention (the invention of claim 2) is applied in such a case. In FIG. 3, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and description thereof will be omitted. N base stations 4 having the same configuration as the base station 41 in FIG.
1 ₁ ... 41 _n are provided. When n base stations are provided in the configuration shown in FIG. 1 based on the provision of n base stations, the same reference numerals as those in FIG. That is, in the base station, each reference numeral of each unit in FIG. 1 is attached with a subscript of 1 or n. In the optical interface device 51, n transmission / reception changeover switches 53 ₁ ... 53 _n
, The movable terminals are connected to the corresponding ones of the base stations 41 ₁ ... 41 _n , and the fixed terminals 53a ₁ ... 53a _n are connected to the coupler 65 through the frequency conversion circuits 64 ₁ ... 64 _n , and the coupler 65. The output side of is connected to the input side of the E / O 16. The output side of the band pass filter 55 is a distributor 66.
Connected to the transmission / reception selector switch 53.
They are respectively connected to the ₁ ... 53 _n fixed terminals 53b ₁ ... 53b _n of. Output side of the frequency converting circuit 56 is connected to the distributor 67, the n distribution output terminal is connected to the antenna terminal 41b ₁ ... 41b _n of the base station 41 ₁ ... 41 _n.

In the radio base station device 52, the output side of the O / E 19 is connected to the distributor 68, the n-distribution output terminals thereof are connected to the frequency conversion circuits 69 _{1 to} 69 _n , and the output side thereof is the transmission amplifier 21. is connected to the movable terminal of the antenna selection switch 57 ₁ ... 57 _n through ₁ ... 21 _n. Antenna selection switch 57 ₁ ~57 _n of fixed terminals 57a ₁ ...
57 a _n is connected to the coupler 71, and the output side of the coupler 71 is connected to the fixed terminal 58 a of the transmission / reception changeover switch 58. Fixed terminal 5 for antenna selection switch 57 ₁ ... 57 _n
7b ₁ ... 57b _n are connected to the coupler 72,
The output side of is connected to the fixed terminal 59a of the transmission / reception changeover switch 59. Other configurations are the same as those in FIG.

In the downlink, the base station 41₁… 41_n
Switch 43₁… 43_nThe output signal from the movable terminal of
Switch 53 in the interface device 51₁... 53_nNiso
Each is entered. Switch 53₁... 53_nIs send thai
Each terminal 53a when mingling₁... 53a_nConnected to
Terminal 53a₁... 53a_nTo frequency conversion circuit 64 ₁
… 64_nAre input respectively. Radio electrical signal frequency
Conversion circuit 64₁… 64 _nUsed in this mobile communication system
Frequency band that does not overlap with the signal frequency band used, and
The signals are respectively converted into signals having different frequencies. frequency
Number conversion circuit 64 ₁… 64_nThe output signal of
After being combined, it is converted to an optical signal by E / O16
It is transmitted to the station device 52. In the wireless base station device 52
Then, the wireless electric signal output from the O / E 19 is sent to the distributor 6
N is divided by 8 and the frequency conversion circuit 69₁… 69_nEnter in
Is done. The radio electric signal is a frequency conversion circuit 69.₁… 69_n
Then, the frequency conversion circuit 64 in the optical interface device 51
₁… 64_nOf the input signal frequency of
After being filtered, each wave is extracted, and each amplifier 21₁…
21_nIs input to These amplifiers 21₁… 21_nIncrease
The width outputs are combined by the combiner 71 and are transmitted by the antenna 45 to the
Is emitted as
It is radiated as a radio wave from the tenor 46.

In the uplink, the band-pass filter 55 in the optical interface device 51 extracts the received signal of the antenna 45 and divides it n by the distributor 66, and then passes it through the switches 53 ₁ ... 53 _n to the base station 41. ₁ … 41
It is supplied to each of the _n antenna terminals 41a ₁ ... 41a _n .
The output signal of the frequency conversion circuit 56 is divided into n by the distributor 67, and then the antenna terminal 41b of the base station 41 ₁ ... 41 _n.
1 ... 41b _n , respectively.

FIG. 4 shows an embodiment of the invention of claim 4. This embodiment is a case where a plurality of base stations are used as in the embodiment shown in FIG. 3. However, the difference from FIG. 3 is that the upstream signal also corresponds to each n base stations, and the antennas 45, It is the same as FIG. 3 in that the frequency band and the frequency of each 46 are converted so as to be different from each other and transmitted through the optical fiber 31. That is, the received amplified output from the antenna 45 is divided into n by the distributor 81 and the frequency conversion circuits 82 ₁ ... 8
2 _n , and the received amplified output from the antenna 46 is divided into n by the distributor 83, and the frequency conversion circuits 84 ₁ ... 84 _n
Supplied to The converted output signals of the frequency conversion circuits 82 ₁ ... 82 _n have different frequencies from each other, and the frequency conversion circuit 8
The converted output signals of 4 ₁ ... 84 _n also have different frequencies,
Moreover, both of these n converted output signals are in a frequency band outside the frequency band used in this mobile communication system. The output signals of the frequency conversion circuits 82 ₁ ... 82 _n , 84 ₁ ... 84 _n are combined by the combiner 85 and supplied to the E / O 29.

In the optical interface device 51, the O / E 32
Of the output electric signal of the
87 _n are respectively input to the frequency conversion circuits 87 ₁ ... 87 _n , and the signals having the same frequency as the input signal of the frequency conversion circuits 82 ₁ ... 82 _n of the wireless base station device 52, that is, the reception signal of the antenna 45. Is converted to and supplied to the fixed terminals 53b ₁ ... 53b _{n of} the transmission / reception changeover switches 53 ₁ ... 53 _n . The other n distributed outputs of the distributor 86 are supplied to the frequency conversion circuits 88 ₁ ... 88 _n , respectively, and are the same as the input signals of the frequency conversion circuits 84 ₁ ... 84 _n of the radio base station device 52, that is, the reception signals of the antenna 46. 4 _n , which are converted into frequency signals and are antenna terminals 41 b ₁ ... 4 _n of the base stations 41 ₁ ... 41 _n .
1b _n respectively.

In the downlink, the base stations 41 ₁ ... 41 _n
The output signals of the switches 43 ₁ ... 43 _n therein are input to the frequency converters 64 ₁ ... 64 _n inside the optical interface device 51, respectively. In the frequency conversion circuits 64 ₁ ... 64 _n , the radio electric signals are frequency-converted into frequency arrangements which do not overlap with each other in the frequency band used by the mobile communication system and do not interfere with each other by intermodulation distortion and harmonic distortion. , And are combined by the combiner 65.

In the uplink, antennas 45 and 4
The received signal of _No. 6 is divided into n by distributors 81 and 83, and is input to frequency conversion circuits 82 ₁ ... 82 _n and frequency conversion circuits 84 ₁ ... 84 _n , respectively. In the frequency conversion circuits 82 ₁ ... 82 _n , 84 ₁ ... 84 _n , the radio electric signals do not overlap with the signal frequency band used in this mobile communication system, and the frequency arrangement is such that intermodulation distortion and harmonic distortion do not interfere with each other. Combiner 85 after frequency conversion
Are joined by. The output signal of the coupler 85 is converted into an optical signal by the E / O 29, and is input to the O / E 32 in the optical interface device 51 via the optical fiber 31. O / E3
The radio signal output from 2 is input to the distributor 86, and 2n is distributed to the frequency conversion circuits 87 ₁ ... 87 _n , 88 ₁ ... 88 _n . Frequency conversion circuit 87 ₁ ... 87 _n , 88 ₁ ... 8
In 8 _n , the frequency of the input signal is converted to the frequency band of the wireless section, that is, the frequency band used between the mobile terminal 26 and the wireless base station device 52, and is output for each wave. The output signals of the frequency conversion circuits 87 ₁ ... 87 _n are output to the terminals 53b ₁ ... 53b _n of the switches 53 ₁ ... 53 _n , and the output signals of the frequency conversion circuits 88 ₁ ... 88 _n are the base station 41 _1.
... 41 _n in switches 41 ₁ ... 44 _n , respectively.

As described above, the frequency conversion circuit 64₁… 6
4_n, 82₁… 82_n, 84₁… 84_nIn each other
Arrange frequency so that modulation distortion and harmonic distortion do not interfere.
Under the frequency band used in the mobile communication system
Limit channel frequency, channel spacing, upper limit frequency,
Due to the frequency of the input channel and the third harmonic distortion
Avoid frequency interference conditions and harmonic distortion interference
It is easy to find the conditions for frequency allocation in
The frequency arrangement that simultaneously satisfies for that reason
Supply to each frequency conversion circuit according to the transmission channel frequency
To change the local signal frequency to
Is a frequency synthesizer as its local signal generating means.
Is used. Therefore, the frequency conversion circuit 69₁… 6
9_n, 82₁… 82_n, 84₁… 84_nThen local signal
A frequency synthesizer is used as a living instrument. Meanwhile, Zhou
Wave number conversion circuit 64₁… 64_n, 87₁… 87_n, 88₁
… 88 _nAs its local signal generator has a fixed frequency
It may be one that outputs a signal. That is, the frequency conversion circuit 64
₁… 64_nFrequency of its input signal to a fixed frequency band
Converting and frequency converting circuit 87₁… 87_n, 88₁… 88
_nThen, the frequency conversion circuit 82₁… 82_n, 84₁… 84
_nOne of the fixed frequency radio signals output from
To the frequency band of the wireless section.

[0029]

As described above, the present invention uses TDD as a radio access system, and a base station and a plurality of mobile terminals that share an antenna for transmission and reception are connected via an optical interface device and a radio base station device. A communication system for connecting an optical interface device and a radio base station device with an optical fiber can be realized by controlling the terminal connection of an antenna selection switch and a transmission / reception changeover switch in the base station. Moreover, the conventional base station can be used as it is.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an embodiment of the invention of claim 3;

FIG. 3 is a block diagram showing an embodiment of the invention of claim 2;

FIG. 4 is a block diagram showing an embodiment of the invention of claim 4;

FIG. 5 is a block diagram showing a wireless zone expansion device using an optical fiber booster system in a conventional cellular system.

FIG. 6 is a block diagram showing a configuration of a conventional PHS base station.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04B 10/12

Claims (4)

[Claims] 1. A mobile communication system in which a base station is connected to a wireless base station device separated from the base station via an optical interface device, and the base station communicates with a mobile terminal via the wireless base station device. In the area expansion device, a transmission antenna selection switch is connected to the output side of the modulator of the base station, and a first fixed terminal of the transmission antenna selection switch and an input side of the first demodulator are connected by a first transmission / reception changeover switch. One antenna terminal is switched and connected, and the second fixed terminal of the transmission antenna selection switch and the input side of the second demodulator are switched and connected to the second antenna terminal by the second transmission / reception changeover switch, and the TDD (Time Div
ision Duplexing: time-division simultaneous transmission / reception is used, and an optical / electrical converter for converting an electric signal into an optical signal, an optical / electrical converter for converting an optical signal into an electric signal, and the optical / A band pass filter for extracting a signal of a predetermined band from an electric signal from the electric converter, and a movable terminal of the second transmission / reception changeover switch by converting an electric signal output from the optical / electric converter into a signal of a predetermined frequency A radio frequency conversion circuit for supplying the electric power to the input side of the electric / optical converter and an output side of the band pass filter for connecting a movable terminal of the first transmission / reception changeover switch to the wireless side. An optical / electrical converter for converting an optical signal from the electric / optical converter into an electric signal, an antenna selection switch connected to an output side of the optical / electrical converter, and a moving end in the base station device. A first and a second antenna for transmitting and receiving radio waves to and from the first antenna; a first transmission / reception changeover switch for connecting the first antenna to a first fixed terminal of the antenna selection switch or an input side of a first reception amplifier; A second transmission / reception switch for switching and connecting the second antenna to the second fixed terminal of the antenna selection switch or the input side of the second reception amplifier, and the output signal of the second reception amplifier in the optical interface device. A frequency conversion circuit for frequency conversion to the same frequency as the frequency of the electric signal supplied to the frequency conversion circuit, and an output signal of the frequency conversion circuit,
An optical / electrical converter for converting an output signal of the first reception amplifier into an optical signal and supplying the optical signal to the optical / electrical signal conversion circuit in the optical interface device, the transmission antenna selection switch in the base station Is connected to a first fixed terminal of the first transmission / reception changeover switch, and the first and second transmission / reception changeover switches in the base station, the transmission / reception changeover switch in the optical interface device, and the wireless base station device The first and second transmission / reception changeover switches,
A mobile communication area expansion device characterized by being switched in synchronism to enable bidirectional communication. 2. The number of the base stations is n (n is an integer of 2 or more)
The optical interface device is provided with n of the transmission / reception changeover switches, the movable terminals of the transmission / reception changeover switches are respectively connected to the movable terminals of the first changeover switches of the n base stations on the input side, The first fixed terminals of the n transmission / reception changeover switches shift the frequency bands of the electric signals, respectively, and convert the n second frequency conversion circuits that convert the electric signals into signals of different frequencies, and these n second frequency conversion circuits. A combiner that combines the output signals and supplies the combined signal to the electro-optical converter, and the output of the band-pass filter are distributed by n,
A first distributor for supplying the second fixed terminals of the n transmission / reception changeover switches, respectively, and a first distributor for distributing the output signal of the frequency conversion circuit into the second antenna terminals of the n base stations. Two distributors, and the antenna selection switch is connected to the wireless base station device.
In each of the n frequency conversion circuits in the optical interface device, a plurality of distributors for distributing the output electric signal of the optical / electrical converter into n and the n distributed outputs of the distributor are respectively supplied. N frequency conversion circuits that convert the signals into the frequency signals before conversion and respectively supply the movable terminals of the n antenna selection switches and the output signals of the first fixed terminals of the n antenna selection switches are combined. For supplying to the first fixed terminal of the first transmission / reception changeover switch
It has a coupler and a 2nd coupler which synthesize | combines the output signal of the 2nd fixed terminal of the said n antenna selection switch, and supplies it to the 1st fixed terminal of the said 2nd transmission / reception changeover switch. Item 1. A mobile communication area expansion device according to item 1. 3. A mobile communication system in which a base station is connected to a wireless base station device separated from the base station via an optical interface device, and the base station communicates with a mobile terminal via the wireless base station device. In the area expansion device, a transmission antenna selection switch is connected to the output side of the modulator of the base station, and a first fixed terminal of the transmission antenna selection switch and an input side of the first demodulator are connected by a first transmission / reception changeover switch. The second fixed terminal of the transmission antenna selection switch and the input side of the second demodulator are switched and connected to the second antenna terminal by the second transmission / reception changeover switch, and the TDD (Time Div
ision Duplexing: time-division simultaneous transmission / reception) is used, and the optical interface device includes an electric / optical converter that converts an electric signal from the first antenna terminal of the base station into an optical signal; An optical / electrical converter for converting an optical signal into an electric signal, wherein the wireless base station device converts the optical signal from the optical interface device into an electric signal, and the electric signal to the optical signal. To an optical / electrical converter in the optical interface device, an antenna for transmitting / receiving radio waves to / from the mobile terminal, and an antenna for outputting the antenna to the output side of the optical / electrical converter. A transmission / reception changeover switch that is switchably connected to the input side of the electric / optical converter, and the transmission antenna selection switch in the base station is fixed to a first fixed terminal of the first transmission / reception changeover switch. The first transmission / reception changeover switch fixedly connects the first fixed terminal to the first antenna terminal, and the second transmission / reception changeover switch fixedly connects the second fixed terminal to the second antenna terminal. A mobile communication area expansion device, characterized in that the transmission / reception changeover switch in the radio base station device is switch-controlled to enable bidirectional communication. 4. A mobile communication system in which a base station is connected to a radio base station device separated from the base station via an optical interface device, and the base station communicates with a mobile terminal via the radio base station device. In the area expansion device, a transmission antenna selection switch is connected to the output side of the modulator of the base station, and a first fixed terminal of the transmission antenna selection switch and an input side of the first demodulator are connected by a first transmission / reception changeover switch. The second fixed terminal of the transmission antenna selection switch and the input side of the second demodulator are switched and connected to the second antenna terminal by the second transmission / reception changeover switch, and the TDD (Time Div
ision Duplexing: time-division simultaneous transmission / reception) is used, and the number of the base stations is n (n is an integer of 2 or more), and the optical interface device has the first movable terminal of the n base stations. The frequency bands of electric signals are respectively shifted to the n transmission / reception changeover switches connected to the movable terminals of the changeover switch and the first fixed terminals of the n transmission / reception changeover switches, and intermodulation distortion and harmonic distortion interfere with each other. N frequency conversion circuits for converting into signals of such frequencies, a coupler for combining output signals of these n frequency conversion circuits and supplying the combined signals to the electric / optical converter, and an optical / electrical converter. A distributor for distributing the output signal of the converter into 2n and n distribution outputs from the distributor are supplied, the frequency bands are shifted, the signals are converted into signals of different frequencies, and each of the n transmission / reception is performed. Correspondence between the n second frequency conversion circuits supplied to the second fixed terminal of the spare switch and the remaining n distribution output signals of the distributor with the frequencies of the output signals of the n second frequency conversion circuits. And a third frequency conversion circuit, which is connected to the movable terminals of the second changeover switches of the n base stations, respectively. Is supplied with an optical signal from the electrical / optical converter in the optical interface device, and an optical / electrical converter for converting the optical signal into an electrical signal and an output electrical signal of the optical / electrical converter A first distributor for distributing signals,
A first frequency converter circuit for converting each of the n output signals of the first distributor into a signal of the same frequency as the corresponding signal frequency of the signal frequency before conversion of the electric / optical converter in the optical interface device; Movable terminals are respectively connected to the output sides of the n first frequency conversion circuits, and n antenna selection switches that are interlocked with each other and a first coupling that combines the output signals of the first fixed terminals of these antenna selection switches Device, a second combiner for combining output signals of the second fixed terminals of the n antenna selection switches, first and second antennas for transmitting and receiving radio waves to and from the mobile terminal, and first and second
A receiving amplifier, a first transmission / reception change-over switch for switching and connecting the first antenna to an output side of the first coupler and an input side of the first receiving amplifier, and the second antenna to the second antenna.
A second transmission / reception change-over switch that is switch-connected to the output side of the coupler and the input side of the second reception amplifier, and second and third output circuits that divide the respective output signals of the first and second reception amplifiers into n.
Distributor and n second frequency converters for converting the n distributed output signals of the second distributor into signals of the same frequency as the input signals of the n second frequency conversion circuits in the optical interface device, respectively. Circuit, and n number of third frequency conversion circuits for converting the n-divided output signals of the third distributor into signals of the same frequency as the input signals of the n number of third frequency conversion circuits in the optical interface device. A third combiner for combining the output signals of the n second frequency conversion circuits and the output signals of the n third frequency conversion circuits, and the output signal of the third combiner to an optical signal. And an electrical / optical converter for supplying the optical / electrical converter in the optical interface device, and a signal input to the third combiner is configured to prevent intermodulation distortion and harmonic distortion from interfering with each other. 2, 3rd frequency The conversion frequency of the conversion circuit is set, the antenna selection switches of the n base stations are fixedly connected to the first fixed terminals, respectively, and the first and second transmission / reception changeover switches of the n base stations are set. And that the n transmission / reception changeover switches of the optical interface device and the first and second transmission / reception changeover switches of the radio base station device are synchronously switched to enable bidirectional communication. A characteristic mobile communication area expansion device.